Many of the radiographic parameters essential to total hip arthroplasty (THA) component performance, such as wear, and stability, can be assessed intraoperatively with fluoroscopy. However even with intraoperative fluoroscopic guidance, the placement of an implant or the reduction of a bone fragment may still not be as close as desired by the surgeon. For example, mal-positioning of the acetabular component during hip arthroplasty can lead to problems. For the acetabular implant to be inserted in the proper position relative to the pelvis during hip arthroplasty requires that the surgeon know the position of the patient's pelvis during surgery. Unfortunately, the position of the patient's pelvis varies widely during surgery and from patient to patient. During trauma surgery, proper fracture management, especially in the case of an intra articular fracture, requires a surgeon to reduce the bone fragment optimally with respect to the original anatomy in order to: provide the anatomical with joint the best chance to rehabilitate properly; minimize further long term damage and, if possible, to regain its normal function. Unfortunately, in a fracture scenario, the original anatomical position of these bone fragments has been compromised and their natural relationship with the correct anatomy is uncertain and requires the surgeon to use his/her best judgment in order to promote a successful repair and, subsequent positive outcome.
Various devices are known to reduce mal-positioning of these surgical components. For example, a transverse acetabular ligament has been suggested as a qualitative marker of the orientation of the acetabulum, (Archbold H A, et al. The Transverse Acetabular Ligament; an Aid to Orientation of the Acetabuiar Component During Primary Total Hip Replacement: A Preliminary Study of 200 Cases Investigating Postoperative Stability, J Bone Joint Surg B R. 2006 July; 88(7):883-7). However, it has been suggested that the acetabulum may be deteriorated due to arthritis. Others have proposed using a tripod device that uses the anatomy of the ipsilateral hemi pelvis as the guide to position the prosthetic acetabular component. U.S. Patent Publication Number 20090306679. This instrument has three points. The first leg is positioned in the area of the posterior inferior acetabulum, a second leg is positioned in the area of the anterior superior iliac spine and a third leg is positioned on the ileum of the subject. U.S. Patent Publication Number 20090306679. Regarding fracture fixation, or a correction of a deformity or malunion, various devices have also been suggested to support proper reconstruction and/or reduction of bone fragments. For example, a distal radius volar fixation plate has been suggested to act as an invasive, intraoperative quantitative supporting buttress to fix and provide a reference to the surgeon in order to help realign the broken bony anatomy.
Distortion in a radiographic image, particularly fluoroscopic images, is a well-known phenomenon (Jareš V. The effect of electron optics on the properties of the x-ray image intensifier. Adv Electron Elect Phys. 10-9-85; 64(8): 549-59). Several distortion correction techniques have been published to date, for example by Kedgely A E, et al, in J Appl Clin Med Phys. 2012 Jan. 5; 13(0:3441. doi: 10.1120/Jacmp.v13i1.3441. Image intensifier distortion correction for fluoroscopic RSA: the need for independent accuracy assessment. These methods attempt to correct the distortion using a series of beads to calibrate the amount of distortion in an image and then attempt to correct that distortion to a non-distorted view of the image. A need exists in the industry to allow for intraoperative live adaptation of a grid (analogue, virtual, augmented, hologram, or 3D shape model) for use in measurements, positioning of implants and alignment of anatomy and to provide distortion adaptation with a radiographic grid alignment device.